1. Field of the Invention
This invention relates to measuring fluid flow. In particular, the invention relates to measuring fluid flow using a multiplicity of sensors and, more particularly, to such measurement of fluid flow in situations in which the fluid flow is anticipated to be turbulent. This invention is also related to measuring fluid flow in the vicinity of an animate object and using such measurement, together with knowledge of the characteristics of the animate object and, if relevant, of one or more objects in the vicinity of the animate object to determine an intention of, or an effect produced by, the animate object.
2. Related Art
Previously, fluid flow has been measured using devices such as an anemometer. An anemometer typically uses one or a few (e.g., four or less) sensors to measure the temperature of a fluid, from which a description of one of a limited number of characteristics of the fluid flow (e.g., velocity) is determined. Typically, anemometers are used to measure laminar flows, since the orderliness of such flows enables sufficiently accurate measurements to be obtained with the small number of sensors characteristic of an anemometer.
Fluid flow measurement has previously been used to determine the characteristics of a fluid flow in the vicinity of an inanimate object, such as the wing of an airplane or the chassis of an automobile. In many cases, such fluid flows are laminar. Fluid flow in the vicinity of an animate object (e.g., a human) can often be turbulent as a result of motion of an unaerodynamic body part (e.g., the hand) or breathing. Anemometers and other existing flow measurement devices may not be adequate to provide sufficiently detailed information regarding turbulent flows. Additionally, analysis of fluid flow in the vicinity of an animate object has not been used to discern an intention of, or an effect produced by, the animate object.
The invention enables fluid flow measurements to be obtained in the vicinity of an animate object (e.g., human) and used, together with knowledge of the characteristics of the animate object and, if relevant, of one or more objects in the vicinity of the animate object, to determine an intention of, or an effect produced by, the animate object. Fluid flow can be measured using an apparatus including a multiplicity of data sensors arranged in a manner that enables acquisition of detailed information regarding the fluid flow. In particular, the fluid flow measuring apparatus can advantageously be used in situations in which the measured fluid flow is anticipated to be turbulent, which is typically the case when measuring the fluid flow in the vicinity of an animate object.
In one embodiment, the invention provides an interface controlled by an animate object by measuring fluid flow in the vicinity of the animate object and determining an intention of, or an effect produced by, the animate object, based upon the measured fluid flow and knowledge of one or more characteristics of the animate object. The fluid flow measurement apparatus can be attached to the animate object. For example, the fluid flow measurement apparatus can be attached in the vicinity of the mouth of the animate object. By measuring fluid flow in the vicinity of the mouth of an animate object, breathing can be measured. Breath measurement, as described more fully below, can be used as a control mechanism. The fluid flow measurement apparatus can also be attached in the vicinity of a movable part of the animate object. By measuring fluid flow in the vicinity of a movable part of an animate object, motion of that part of the animate object can be measured. Such motion can, for example, be interpreted as gestures and used to effect corresponding control.
Any appropriate fluid flow measuring apparatus can be used. For example, the fluid flow measuring apparatus can be an apparatus adapted to sense temperature. (Temperature sensors can be desirable because they are often relatively inexpensive.) Such a fluid flow measuring apparatus could be implemented using one or more semiconductor devices. In particular, such sensor(s) can be implemented using a junction diode. A fluid flow measuring apparatus adapted to sense temperature could also be implemented using one or more thermocouples, or one or more thermistors. A fluid flow measuring apparatus for use with the invention can be implemented with other types of devices as well. For example, the fluid flow measuring apparatus can be an apparatus adapted to sense mechanical deflections, such as devices that include a piezoelectric transducer or devices that include a strain gauge.
It is anticipated that in many applications for which the invention will be used, the measured flow will be turbulent. It is, therefore, desirable that the fluid flow measurement apparatus include a relatively large number of sensors, since the acquisition of a large amount of data regarding the fluid flow may be necessaryxe2x80x94and is, at least, desirablexe2x80x94to ensure that the fluid flow is measured with adequate accuracy and comprehensiveness. Acquisition of a large amount of data can also enable more complex analysis of the data. Thus, a fluid flow measuring apparatus in accordance with the invention preferably uses more sensors than have been used in anemometers or other previous fluid flow measuring apparatus. In one embodiment of the invention, a fluid flow measuring apparatus according to the invention includes 5 or more sensors. Further, the sensors of a fluid flow measuring apparatus for use with the invention can advantageously be arranged in an array of two or more dimensions, thus enabling measurement of fluid flow in a corresponding number of dimensions.
In another embodiment, the invention measures fluid flow by measuring the voltage across the semiconductor junction of each of one or more data sensors, determining the temperature of the one or more data sensors based upon the voltage across the semiconductor junction of the data sensor, and determining a description of one or more characteristics of the fluid flow using one or more data sensor temperatures. The data sensor(s) can be, for example, junction diode(s). The data sensors can be arranged in an array of two or more dimensions. In a particular implementation of this embodiment of the invention, five or more data sensors are used.